Remote operations, such as the handling of radioactive materials or driving unmanned vehicles, require rapid visual feedback to a human operator. For some applications, such as micromanipulation in surgery or conducting repairs or inspections in spaces inaccessible to humans, optical devices such as microscopes, telescopes, or optic fiber bundles can be used to direct imagery to the operator.
However, over long distances optical devices are not practical in presenting imagery to the operator in that light losses become too large or image focus cannot be maintained. It is common in these cases to encode an image into a signal whose elements represent small components of the image and to subsequently reconstruct the image at the destination. Video is one example. An analog signal is constructed electronically from the light intensity at tiny spots in a pickup camera. The signal is decoded at the receiver, where light intensity is reconstructed at corresponding spots in a display.
Because there are so many spots of light to encode and transmit to obtain a reasonable degree of image resolution a bandwidth for video imagery is very high. In applications where the image pickup device is fixed, and the operator has control of the space between image pickup and operator, dedicated coaxial transmission lines can be used to transmit imagery. When the remote image pickup is mobile, however, the transmission lines must be flexible and tethered between the remote and the operator site. Alternatively, electromagnetic (radio) waves can be used as a carrier. The high bandwidths of video imagery typically requires microwave transmission, which restricts the relative position between remote image pickup and the receiver to line-of-sight transmission. However, line-of-sight transmission may be a serious restriction. Within buildings, transmission around corners or through walls is impossible. In military unmanned vehicles, the transmitter is required to operate from exposed positions on crestlines of hills.
It is therefore an object of the invention to provide visual data encoding which reduces an amount of data required to represent an image, and to subsequently decode the compressed imagery into a form which is recognizably perceived by the human viewer.
It is a further object of the invention to compress the image data by matching the parameters of the encoded information to the parameters of human visual perception, and to provide a decoding technique which faithfully reproduces the parameters in a displayed image.
It is another object of the invention to encode image information in such a manner that the center of the field of view is represented at high resolution, with peripheral resolution being progressively coarser in proportion to distance from the center.
It is another object of the invention to encode real-time (30 images per second), wide field of view, color imagery with high central resolution and lower peripheral resolution, and in such a manner that the encoded imagery can be transmitted by RF waves through air or vacuum without line-of-sight restrictions.